Ultrasound-assisted extraction of yerba mate leaves for the development of active additives in sports nutrition products

Abstract

This study aimed to develop yerba mate extracts (YME, Ilex paraguariensis) as active ingredients for a UVC-light-preserved (892 mJ/cm²; 50°C) sports drink (SD) and the sports gel derived from it (SG). Aqueous ultrasound-assisted extractions (US; 20 KHz, 750 W) of yerba mate leaves were performed at varying temperatures (T: 20, 40, and 50 °C) and acoustic energy densities (AED: 0, .11, and .23 W/mL). Total polyphenol (TPC) extraction kinetics were characterized using the Spiro and Jago, Linares, and Peleg models. The Spiro and Jago model accurately described the extraction kinetic curves. An empirical correlation was found between its rate constant and the variables T and AED, reaching its maximum value at 50°C–.23 W/mL, with no further TPC extraction beyond 4  minutes (4.20 g GAE/L). For comparison purposes, the conditions 20°C/.23 W/mL/7 min (3.33 g GAE/L) and 100°C/0 W/mL/5 min (control) were also structurally and physiochemically compared. During the extraction, intraparticle diffusion was one of the major mechanisms limiting the extraction rate. With AED and T, the intraparticle coefficient increased significantly. The US-assisted process generated extracts with greater wettability, hygroscopicity, more natural color, and similar content of relevant xanthin alkaloids and polyphenols, compared to the control. SEM micrographs revealed that the US-assisted extract's porosity increased with AED and T. The UV-C processing of SD was successfully validated through microbial challenge assays. YME (20°C/.23 W/mL/7 min) addition turned SD and SG greener and raised their flavonoid content (SD: 5.2-fold and SG: 19.6-fold) and TPC (SD: 5.5-fold and SG: 5.3-fold). The DPPH and ABTS total antioxidant activity for SD and SG increased by 3.1–3.4-fold and 16.8–57.9-fold, respectively. SD-YM and SG-YM were well-accepted and described in a consumer field test. The developed YMEs can be a natural source of xanthine alkaloids and polyphenols, thereby replacing the synthetic additives typically employed in sports nutrition products.

Practical applications

The growing consumer belief in natural extracts' ability to promote health and wellness is driving the global market for botanical extracts. Yerba mate (Ilex paraguariensis St Hill) is a healthier alternative to coffee and tea, with higher antioxidant capacity and proven health benefits. The proposed extraction method eliminates the need for high temperature and prolonged treatments, preserving the nutritional value of yerba mate leaves. Furthermore, it eliminates waste generation, perfectly aligning with sustainable practices. The optimized US-assisted extraction resulted in high-quality physicochemical extracts with significant functional activity. Amateur athletes are increasingly looking for products to enhance their performance that are both natural and effective. In this context, the developed extracts can serve as natural additives for sports nutrition products, which typically include synthetic caffeine and other compounds aimed at enhancing alertness, arousal, and energy.